In the prior art it is known that the field of optic devices includes many solid state devices that operate as optical waveguides for optical communications systems-- see the publication "Survey of Integrated Optics," S. E. Miller, IEEE Journal of Quantum Electronics, Volume QE-8, No. 2, February, 1972, pp. 199-205. Recently developed thin film technology has permitted the fabrication of miniature, solid state devices that permit the transfer of optical power from a thin film structure to an associated optical fiber transmission line--see the I. P. Kaminow, et al, published patent application No. B 381,985, published Feb. 3, 1976.
In the co-pending patent application of G. F. Sauter, et al, Ser. No. 709,468, filed July 28, 1976, now U.S. Pat. No. 4,082,424, there is disclosed an integrated optic device including a diffraction grating consisting of a stripe domain garnet film that is in intimate contact with a suitable waveguide member, both supported by a suitable substrate member. A laser beam that is directed incident to the surface of the stripe domain garnet film is selectively, varyingly coupled to the waveguide (modulated in intensity) and is selectively, varyingly directioned along the plane of the waveguide to be directed upon a selected one of a plurality of couplers for retransmission to an associated optic fiber transmission line (multiplexed). The magnetic film stripe domain diffraction grating and the method of the operation thereof of the E. J. Torok, et al, U.S. Pat. No. 3,752,563 are utilized as the means for coupling, modulating and multiplexing the laser beam to and within the optical waveguide for subsequent processing of the data that is borne by the laser beam. In this apparatus and method, the light beam is limited to a single mode, single frequency light beam because of the use of the intermediate waveguide. The present invention is considered to be an improvement of such prior art optic device in that the present invention may use a multimode, multifrequency light beam for signal transmission whereby the design limitations of the apparatus are substantially reduced resulting in a simplified optical multiplexer of data-modulated light beams.